...The Greatest 20 Years of Music

Every generation says that the music they listened to was the best music of all time. It's bound to happen, you're surrounded by the stuff, it sinks into your developing mind and stays there. Add a dash of nostalgia for childhood and nothing can compare to that concoction.
Still, I need to through my chips in for the music of the '80's and '90's,. You see, I was born in 1980, so my first experiences with music were the death of disco and the rise of heavily synthesized New Romanticism and Glam Rock. Goth broke from punk and began it's march to fame in the 80's, and hip-hop began to find it's foothold during the decade of my birth. There was also the nebulous "New Wave" term that got bandied about, and nowadays has come to mean "Just about anything produced in the '80s".
This was a great, but incredibly commercial, time for music. Many bands, such as Dexy's Midnight Riders, produced a lot of good music, but never got aware until they toed the line and released "Come On Eileen", the only single they are currently known for (much to the chagrin of the former lead singer). Even the band Genesis, founded by Peter Gabriel, found only underground success until Gabriel left the band and Phil Collins helped move the band into a more pop-oriented direction.
Now that's not to say that some great and lasting things didn't come out of the '80's. The aforementioned Genesis saw lots of success that still endures and helped to launch Phil Collins' solo career. Hall and Oates are still popular, Billy Idol's fusion of punk and pop laid the groundwork for bands that would take up the pop punk banner in the '90's like Green Day and The Offspring, and rock legends Aerosmith final began to truly tear up the radio as Steven Tyler tore up his vocal cords with a vocal style not experienced before
Modern music owes a lot to the '80's, not only for the '80's use of really catchy hooks that get stuck in your head, but also the power of the visual. Many bands used powerful stage shows (i.e. Pink Floyd) to wow audiences that came to their shows, but it wasn't until the '80's and the rise of MTV that bands could more readily draw fans in through the visual in the form of the music video.
In fact, one of the downsides of the '80's was the huge amount of one hit wonders that sprang up and faded in the decade. In general, only the one single that made them famous is the one that survives today.
Let's play a game, I'll name a band, you name the hits you know from them. Ready?
Dexy's Midnight Riders? (Come on Eileen, right?)
Men Without Hats? (Can you name something other then Safety Dance?)
Thomas Dolby? (She Blinded ME with SCIENCE!)
Stray Cats? (C'mon, there's gotta be more then Rock This Town)
Simple Minds? (To be fair, I'm sure whichever band that recorded Don't Forget About Me would've ridden the Breakfast Club to fame)
While the '80's created a number of great bands, the grand majority where sparkle and fade types that could rarely overcome that one single that made them famous. For a lot of listeners, though, those singles were just enough, and in modern days, most of the catalog of these bands has vanished into obscurity.
The tide turned a bit once the '90's came around, and many will say that it started in Seattle. Generally referred to as Grunge, it represented a less refined, rougher edged kind of rock that seemed to turn it's back completely on the '80's super-produced sound. Grunge's champion is often cited as Nirvana, the band the first showed the wider public this, at first, regional music, opening the door for bands like Soundgarden, Alice In Chains and Pearl Jam to rise to fame.
Post-Grunge (a genre often said to have come to birth after the death of Nirvana's Kurt Cobain) saw Grunge expanded with popularity of bands like Gin Blossoms, CandleBox and Collective Soul.
And that's what made the '90's amazing, the fact the genres seemed to fall apart as bands experimented with sounds and found fame but breaking down what was once thought as a rigid genre structure. Heavy metal bands began incorporating  rap into there music (nu metal), electronic music began to rise to fame (mostly on the shoulders of Nine Inch Nails) and some bands adopted a devil-may-care, hate-me-so-much-you-love-me attitude toward the public (exemplified by Marilyn Manson).
The '90's also saw R&B and soul music taking a strong foothold on the charts, and country exploded as a popular music genre.
Everybody had something to love on the radio at the time. This was also the decade of the term "sell-out" to refer to a formally underground or punk band who suddenly found mainstream success, and instead of denying it (as many fans somehow felt they should) they embraced it and opened up their music to wider audiences.
It seems that almost every modern band has a '90's band on their list of influences, and that's because so much came to a head during that decade and so much memorable music was created. Don't get me wrong, there were a lot of one hit wonders at the time, no one remembers much more then "Closing Time" from Semisonic. Natalie Imbruglia came away with a single hit in the song "Torn" (which is actually a cover), and fellow Aussie rockers Silverchair, though they had a devoted fan base, is forgotten for almost all but "Tomorrow".
But for every one hit wonder, there are at least two bands that made a much larger dent in the landscape. Bands like Nirvana (Smells Like Teen Spirit, Come As You Are and others) Soundgarden (Black Hole Sun, Spoonman, The Day I Tried to Live, etc.) and Pearl Jam (Jeremy, Betterman) still endure as paragons of rock's heyday. Whitney Houston, R. Kelly, even Seal are seen as stars of R&B. The nineties not only launched countless careers, they created sounds and bands considered to be the deities of their genres.

I'm not putting down era's before. Psychedelia is fun from the '60's is good . Bubblegum pop is a good way to spend some innocent fun, and even the "Oh, woe is me, my girlfriend's dead" pop of the '50's is good. There is even some stuff to salvage from modern music, but like I said, that cocktail of immersion and nostalgia is a hard one to beat. That's why I will say that the music of the first 20 years of my life will always be the best music ever created.